Technical Field
The present invention relates to a method of manufacturing a silicon carbide semiconductor device.
Background Art
Conventionally, in the fabrication (manufacturing) of trench-gate MOSFETs (metal oxide semiconductor field effect transistors), a damage layer forms on the trench inner wall during the etching for forming the trench. The “damage” is surface recesses and protrusions caused by disruption of crystalline structures near the surface and surface roughness due to etching.
Performing sacrificial oxidation on the trench inner wall can remove the damage layer on the trench inner wall, but when the semiconductor material is silicon carbide (SiC), performing sacrificial oxidation after the trench is formed is reported to have negative effects on device characteristics (see Patent Document 1 below, for example). In Patent Document 1 below, a gate oxide film is formed without performing sacrificial oxidation after the trench is formed in order to prevent degradation of the reliability of the gate insulating film.